Kanye West thinks celebrities should be allowed to have an ''off day.''

The 'New Slaves' hitmaker, who struck a plea deal with prosecutors in March over allegations he struck photographer Daniel Ramos in an unprovoked attack last summer, opened up about the incident while performing at the Wireless Festival in London on Saturday (05.07.14), and claimed he only lashed out because he was stressed out about his ailing grandfather, Portwood Williams Senior, who died last August.

A source told the MailOnline: ''During his now routine speech during 'Runaway,' he opened up about his paparazzi camera incident. He said he had just been at a deposition in regards to the case and explained that on the day of the incident, he was actually on the phone being told that his grandfather was not going to make it.''

The 37-year-old star, who agreed to perform after Drake cancelled due to illness, was reportedly booed for giving a 20-minute rant about discrimination in the fashion industry during his set on Friday (04.07.14), but his fans were more understanding on Saturday.

The insider said: ''While the crowd cheered at first, they became tired and frustrated as the speech, which once again went on for 20 minutes with Kanye complaining that 'celebrities need to be allowed to have an off day as well.' They began to boo with one section of the crowd saying 'We want Drake.' But they cheered when the speech ended and were actually more receptive than [Friday].''

The rapper, who is married to Kim Kardashian, also admitted he is ''very shy'' and misunderstood.

He said: ''I'm very shy in real life. Because I'm too shy to put out some b*******.''

He added: ''Sometimes it's hard because I'm too shy to carry off a lot. I'm arrogant and shy and a little bit lazy. I'm too shy to lie to anybody and I'm too arrogant to make myself lie to anyone because lies take too much work.''